Calibration
EC, pH and temperature can all be calibrated. 2 values are shown on screen during calibration:
Raw –this shows the un-calibrated reading and indicates how accurate the probe is.
Cal –this shows the calibrated reading which is used for the main display.
To calibrate the Nutritest:
1. Navigate to the appropriate calibration screen.
2. Hold down the up button to increase the calibrated reading or down button to decrease.
3. Once the device has been satisfactorily calibrated press the right key to save and exit. Alternatively
pressing the left key will discard calibration and exit.
To restore the calibration setting to factory default:
4. Navigate to the reset calibration screen and select the reading to reset (pH/EC/Temp).
5. Press the right button and release to reset the reading so that it is un-calibrated. A message will briefly be
displayed confirming that calibration has been reset.
6. To exit the reset calibration screen press the left key.
EC Calibration
The EC calibration should be checked weekly. To do this, place the probe in the 2.77 (CF 27.7) standard
solution and allow to stand for 5 minutes. The reading should be 2.8mS/cm +/- 0.1 mS/cm. If not, navigate to
the EC and follow the steps above until the calibrated reading shows 2.77. Next rinse the probe in fresh water
and shake off excess water.
Temperature Calibration
The temperature sensor is located in the EC probe so to calibrate temperature place the EC probe in a body of
water with a known temperature. The probe should be left in the solution long enough for the probe
temperature to match the solution temperature.
pH Calibration
The pH calibration should also be checked weekly. Calibrating the pH is a more complicated process and
requires a few more steps. It involves 2 stages of calibration: calibrating using a pH7.0 solution and then a
pH4.0 solution. To calibrate the pH:
1. Place the probe in a pH 7.0 buffer solution. Allow about 5 minutes for the pH reading to stabilize then
navigate to the pH calibration screen.
Note: An error message will be displayed and calibration will be disabled until a reading between 6.0 and 8.0.
is sampled. At this point the calibration can be cancelled by pressing the left button.
2. Once the reading has stabilized and is in the above range calibrate the device until the calibrated reading
shows 7.00.
3. Remove the probe and rinse it in fresh water and shake of the excess water.
